Postoperative stroke in patients on oral anticoagulation undergoing coronary artery bypass surgery

Postoperative ischemic stroke and death prediction with CHA2DS2-VASc score in patients having coronary artery bypass grafting surgery: A nationwide cohort study

OBJECTIVES

This nationwide cohort study was attempted to address the predictive ability of CHA2DS2-VASc score in both ischemic stroke and death in patients undergoing coronary artery bypass grafting (CABG) surgery.

METHODS

We identified patients aged ≥18years undergoing de novo CABG between January 1, 2000 and December 31, 2011. We calculated CHA₂DS₂-VASc score for each study patient. We used univariable and multivariable Cox proportional hazards regression models to measure the hazard ratios (HRs) and 95% confidence intervals (CIs) for ischemic stroke and death associated with CHA₂DS₂-VASc score in the study patients. We used the area under the curve of receiver-operating characteristic (C-statistic) to calculate the predictive power of CHA₂DS₂-VASc score with respect to ischemic stroke and death in patients having CABG.

RESULTS

A total of 43,694 patients aged ≥18years receiving de novo CABG were included in the study cohort. The incidence and risk of ischemic stroke and death were positively associated with CHA₂DS₂-VASc score in patients receiving CABG. In addition, the discriminatory properties of the score resulted in C-statistics of 0.60 (95% CI=0.59-0.61) and 0.63 (95% CI=0.62-0.64) for the prediction of ischemic stroke and death in patients undergoing CABG, respectively.

CONCLUSIONS

The present study is the first nationwide cohort study to investigate the performance of CHA₂DS₂-VASc score for the prediction of ischemic stroke and death in patients receiving CABG. However, the discriminative power was modest, and the predictive role of CHA₂DS₂-VASc score in this population remained to be determined.

Use of blood products and risk of stroke after coronary artery bypass surgery

BACKGROUND

The impact of blood transfusion on the development of post-operative stroke after coronary artery bypass grafting (CABG) is not well established. We, therefore, investigated this issue.

MATERIALS AND METHODS

Complete data on peri-operative blood transfusion were available for 2,226 patients who underwent CABG in three Finnish hospitals.

RESULTS

Stroke occurred post-operatively in 53 patients (2.4%). Logistic regression showed that pre-operative creatinine (OR 1.003, 95% CI 1.000-1.006), extracardiac arteriopathy (OR 2.344, 95% CI 1.133-4.847), pre-operative atrial fibrillation (OR 2.409, 95% CI 1.149-5.052), and the number of packed red blood cell units transfused (OR 1.121, 95% CI 1.065-1.180) were significantly associated with post-operative stroke. When the various blood product transfusions instead of transfused units were included in the multivariable analysis, solvent/detergent treated plasma (Octaplas) transfusion (OR 2.149, 95% CI 1.141-4.047), but not red blood cell transfusion, was significantly associated with postoperative stroke. Use of blood products ranging from no transfusion (stroke rate 1.6%) to combined transfusion of red blood cells, platelets and Octaplas was associated with a significant increase in post-operative stroke incidence (6.6%, adjusted analysis: OR 1.727, 95% 1.350-2.209). Patients who received >2 units of red blood cells, >4 units of Octaplas units and >8 units of platelets had the highest stroke rate of 21%. CART analysis showed that increasing amount of transfused Octaplas, platelets and history of extracardiac arteriopathy were significantly associated with post-operative stroke.

CONCLUSIONS

Transfusion of blood products after CABG has a strong, dose-dependent association with the risk of stroke. The use of Octaplas and platelet transfusions seem to have an even larger impact on the development of stroke than red blood cell transfusions.